The goals of the Clinical Core are to: 1) establish a database of HIV subjects seen within the University of Pennsylvania Health System, 2) establish a repository of specimens from HIV patients, and 3) expand and better integrate patient-oriented research on Penn's campus. Approximately 2000 patients are in case at the various HIV clinics in the Health System, including 1850 adult patients and 150 children and adolescents at the Children's Hospital of Philadelphia. An additional 300 IVDU subjects at high risk for HIV infection are followed in the Risk Assessment Program of the Philadelphia Veterans Administration Medical Center. CFAR investigators, study nurses and data managers will establish a patient database that will be managed by investigators in the Epidemiology and Biostatistics Core. Information will be collected on demographics, risk factors, health status, treatment regimens, CD4 counts and viral load that will be used to identify subjects for investigator initiated research. A specimen repository will be established by collecting serum, plasma and PBMCs every six months on HIV outpatients at the Hospital of the University of Pennsylvania and The Children's Hospital of Philadelphia. When invasive procedures are performed on outpatients and inpatients for diagnostic purposes, efforts will be made to collect certain previous specimens, such as spinal fluid, lymph tissue, biopsy and autopsy material. We will use the entire Health System to identify subjects for inclusion in the repository from select population, such as anti-retroviral naive, acute infection, pregnant women , discordant couples, slow or rapid progressors, and patients with dementia or neuropathy. Investigators at Penn have research interests in anti-retroviral therapy, pathogenesis of OIs, HIV DNA vaccines, immune modulators, HIV tropism for macrophages, AIDS dementia and neuropathy, co-receptor use for HIV entry, Kaposi's sarcoma, adherence to therapy, and risk assessment and quality of life measurements. The database and repository will significantly expand the potential for our investigators to enhance understanding of HIV pathogenesis and treatment.